Fears of another pandemic have been raised after a new strain of flu was identified by scientists in China.
The virus, which is being called G4 EA H1N1, has emerged recently and is carried by pigs but can infect humans.
While it is not an immediate problem, researchers say it has “all the hallmarks” of being highly adapted to infect humans and needs close monitoring.
As it’s new, people could have little or no immunity to the virus.
The scientists write in the journal Proceedings of the National Academy of Sciences that measures to control the virus in pigs, and the close monitoring of swine industry workers, should be swiftly implemented.
The new flu strain that has been identified in China is similar to 2009 swine flu, but with some new changes.
So far, it hasn’t posed a big threat, but Prof Kin-Chow Chang and colleagues who have been studying it, say it is one to keep an eye on.
The virus can grow and multiply in the cells that line the human airways.
They found evidence of recent infection starting in people who worked in abattoirs and the swine industry in China.
Current flu vaccines do not appear to protect against it, although they could be adapted to do so if needed.
Prof Kin-Chow Chang, who works at Nottingham University in the UK, told the BBC: “Right now we are distracted with coronavirus and rightly so. But we must not lose sight of potentially dangerous new viruses.”
While this new virus is not an immediate problem, he says: “We should not ignore it.”
Prof James Wood, head of the Department of Veterinary Medicine at the University of Cambridge, said the work “comes as a salutary reminder” that we are constantly at risk of new emergence of pathogens, and that farmed animals, with which humans have greater contact than with wildlife, may act as the source for important pandemic viruses.”